Study on the Optimization and Experimental of Fly Ash and Sludge in Ecological Slope Protection Substrate

At present, adding solid waste in plant substrate to replace part of planting soil has become a new direction in the field of ecological slope protection substrate research. In this paper, 16 groups of indoor orthogonal experiments were carried out with fly ash and sludge as the components of vegetation substrate and tall fescue as the planting object to explore the influence of ecological slope protection substrate on vegetation growth. Based on the range analysis method, the three functions of substrate planting performance, mechanical properties and substrate properties were used as references, and the entropy weight method (EWM) was used to assign weights to the proportion of each index in the total score, and the ratio was optimized. The results show that the optimal substrate ratio is 10% sludge content, 30% fly ash, 4% cement, 6% fiber, 50% planting soil (the ratio of loess and peat soil is 1:3). Fly ash has a great influence on the height of plants and vegetation coverage, and has a significant effect on the internal friction angle and fertility of the substrate. Sludge mainly affects the growth height of plants and the pH value and fertility of the substrate. The importance of factors affecting the growth of plants from large to small is: fly ash, the ratio of loess and peat soil, sludge, rice husk, cement.